East wind - the last line of winter's defense...

Posted January 11th, 2013 by Bill Kardas. 40 comments

First, some stats of our current January thaw- 

7 days in a row above freezing & counting
(longest streak in recent memory was 9 days back in 2008)

7 days in a row without measurable snowfall & counting
(longest streak in recent memory was 11 days also in 2008)

These are impressive numbers for January.  Our thaw isn't done yet as we continue to add more days to this tally.  It won't be smooth sailing though...

RETURN OF THE EAST WIND

Ah yes, the notorious east wind makes a return to Central New York today.  The east wind is an ageostrophic wind caused by local topography.  Ageostrophic is a fancy term that basicially translates to 'what the wind would naturally do without the coriolis force, or rotation of the earth).  Wind naturally wants to move from high pressure to low pressure.  The coriolis force bends the wind to the right of this motion.  That's why low's rotate counterclockwise and highs rotate clockwise.

How do we elimate the coriolis force?  Well, we don't eliminate it because we can't stop the earth from spinning, but we can overcome that force by adding friction.  Friction due to hilly terrain causes winds to bend into the east under the right pressure conditions.  In our case, when high pressure is located east and low pressure to the west, the east wind is strongest.

Why is the east wind cold if it's blowing from the east?  Good question.  In order to answer that, we have to understand local topography's influence on weather.  Take a look at a topographic map of NYS.  You'll notice several 'north/south' oriented valleys connecting the Mohawk River to the Adirondack drainage basin.  Cold air that builds in the Adirondacks will naturally drain down these valleys into the Eastern Mohawk Valley.  Areas from Canajoharie east are slightly climatologically colder year round due to this effect.  An east wind brings that cold air west, something called cold air advection.

Extent & overall effect of the east wind

The east wind gets a bad reputation around here, but in reality it acts more like a 'last line of defense' for snow lovers.  It's important to point out that this effect only happens when warm air is on the way.  The extent of the east wind depends on the scenario.  Many times, the east wind effect extends to Rome.  In most cases it serves to delay *not prevent* a warmup.  The only exception to that rule is areas from Canajoharie east (as mentioned above).

Freezing rain events are more common due to the east wind.  There is a climatological 'spike' in freezing rain occurances in the Mohawk Valley due to this localized effect.  Today, we're confident enough to say that temperatures ought to climb above freezing before our rain event moves in, but we will certainly keep tabs on the east wind.  We've seen many surprises in past years.

The good news is that the east wind can't maintain the cold forever.  Once upper level winds get strong enough, the cold air gets 'scoured out' of the valleys, and temperatures warm up a lot.  Even under ideal conditions, the east wind breaks down after about 24-36 hours.  While the east wind keeps us in the 30s for most of today, we'll easily climb into the 40s by Saturday and 50s on Sunday.

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  1. Bill Kardas (WKTV):

    It’s possible that we see some light freezing rain east today due to evaporational cooling. Our current temperature at Rome is 31° – almost above freezing. However, the dew point though is 23° meaning the air will cool off a bit as the rain arrives. The longer the precipitation takes to get here the less likely it will fall as freezing rain anywhere. We’ll keep you posted.

    Posted January 11th at 8:53 AM

  2. Rob (Whitesboro):

    30 degrees here. First band didn’t reach the ground.

    Posted January 11th at 9:14 AM

  3. sue (fairfield):

    30 here too with a dewpoint of 24

    Posted January 11th at 9:15 AM

  4. Rob (Whitesboro):

    When it precips heavy enough does the air get warm down here because 850’s are so high. Like the opposite when we see evaporational cooling.

    Posted January 11th at 9:19 AM

  5. Bill Kardas (WKTV):

    Rob – good question. No, it doesn’t. Air cools off not because it’s colder aloft, but because liquid water turns to water vapor. That phase change absorbs latent heat. The only way to reverse that effect is to condense water vapor at the surface (create dew/fog).

    Posted January 11th at 10:15 AM

  6. Bill Kardas (WKTV):

    Rome is trending warmer and less dry – up to 33° with a dew point of 25°. Our wet bulb is now 30°, the coolest temperature we could obtain by evaporation. If that thin arm of precip gets here soon it could initially start out as light icing, but there’s a huge gap on the radar between that arm and the next wave. By the time the steady precip gets here it should be warm enough for plain rain. So, unless something changes we should be spared any icing.

    Posted January 11th at 10:26 AM

  7. Rob (Whitesboro):

    Thanks Bill. It’s 32/23 here.

    Posted January 11th at 10:34 AM

  8. Lori (Bridgeport):

    rain …rain …go away.

    Posted January 11th at 11:05 AM

  9. sue (fairfield):

    32 here right now…..was 31 all the way from herkimer…..raining for the last hour or so…...just passed a plow on my road salting…..and exactly Lori, please rain go away ; )

    Posted January 11th at 12:05 PM

  10. Bill Kardas (WKTV):

    This is going to be a close call…next round of rain developing to the west as temperatures remain slightly above freezing. Now up to 35° but the wet bulb is between 31-32°. I have to think there will be some pockets of freezing rain to the east of Utica based on present conditions.

    Posted January 11th at 12:08 PM

  11. Bill Kardas (WKTV):

    From NWS Binghamton:

    ...PATCHY FREEZING DRIZZLE OR LIGHT SLEET INTO THE EARLY AFTERNOON
    HOURS...

    SPOTTY LIGHT PRECIPITATION WILL MOVE THROUGH THE REGION LATE THIS
    MORNING...AND INTO EARLY THIS AFTERNOON. ALTHOUGH TEMPERATURES WILL BE RISING...THEY WILL LIKELY STILL REMAIN BELOW FREEZING IN SOME
    AREAS...ESPECIALLY THE HIGHER ELEVATIONS.

    ANY UNTREATED ROADWAYS OR SIDEWALKS COULD BECOME SLIPPERY FOR A SHORT TIME.

    BY MID TO LATE AFTERNOON...TEMPERATURES ARE EXPECTED TO CLIMB ABOVE FREEZING AREA-WIDE...WITH STEADIER RAIN DEVELOPING AT THAT TIME.

    Posted January 11th at 12:25 PM

  12. Bill Kardas (WKTV):

    Sprinkles are beginning to fall on Smith Hill – wet, not icy here.

    Posted January 11th at 12:42 PM

  13. Rob (Whitesboro):

    It’s pouring here at 32 degrees. Doesn’t seem to be icing up.

    Posted January 11th at 1:10 PM

  14. sue (fairfield):

    pouring here too with same temp…..watching to see potential icing

    Posted January 11th at 1:12 PM

  15. Mel (Westernville):

    A little ice pinging off the windows here.

    Posted January 11th at 1:26 PM

  16. Adam Musyt:

    We’re 34 degrees with a dew point of 28. This yields a wet bulb temperature of 32. So we should be okay in Utica/Rome since the roads are already wet and all of those numbers are only going to be climbing through the afternoon.

    A good shorthand way to find the wet bulb temperature is the “1/3 rule.”

    In order to find the wet bulb temperature you need to find the dew point depression. The dew point depression is just the temperature minus the dew point temperature.

    Once you know the dew point depression you can calculate the wet bulb temperature by dividing the dew point depression by 3 and then subtracting that number from the origional temperature.

    In this case the dew point depression (temperature minus dew point) is 6. The wet bulb temperature then is 34 – (6/3) or 32 degrees.

    Posted January 11th at 1:29 PM

  17. Lori (Bridgeport):

    Im at 34 and still raining …I am glad this never froze on here ….I would be slip sliding all the way into the lake !

    Posted January 11th at 4:31 PM

  18. Brent(802 Feet) (Dolgeville):

    Some slight freezing spots in parking lots. Treated roads seem to be staying decent. Like Lori I am happy it is not much colder. Car was reading 32 degrees.

    Posted January 11th at 5:06 PM

  19. Nick (West Winfield,NY):

    12z EURO looks amazing, Hr 168. wow.

    Posted January 11th at 5:15 PM

  20. Art (Oriskany Falls):

    I sure hope the Barge Canal is low on water because if it rains tonight there will be a lot of runoff water coming off this hill. We could use a melt down of the snow before the rains come. It did rain a bit this afternoon. It would rain for a short period of time and then stop but rained a little harder the last time. The temp. is 34* right now, No freezing rain here,
    Just plain rain. Wind is out of the South, Southwest.

    Posted January 11th at 5:16 PM

  21. Art (Oriskany Falls):

    I have a rain gauge out thinking it’s not going to freeze tonight.

    Posted January 11th at 5:18 PM

  22. Adam Musyt:

    Art – any place in CNY not already below the freezing mark won’t be by later tonight.

    Your gauge should be safe :)

    Posted January 11th at 5:29 PM

  23. Gordon (Northwestern):

    Still 33 degrees here. It has been 33 since 9 AM this morning. With the rain today my snowpack is down to 13.5”.

    Posted January 11th at 6:19 PM

  24. Anthony (Oriskany 565 ft.):

    Great discussion on the East wind. Saranac Lake is warmer than me right now , LoL

    Posted January 11th at 6:20 PM

  25. Rob (Whitesboro):

    Nick that’s brutal cold. That’s the coldest airmass I’ve seen in a long time. Even though we arn’t in the core of it we could easiy hit -20 or so Thursday night. It’s pretty moist too in the upper levels for LES. Usually an airmass like this is bone dry.

    Posted January 11th at 9:23 PM

  26. Michael (Dolgeville):

    31 degrees with light freezing mist. Side roads are slick throughout the towns of Salisbury and Manheim!!

    Posted January 12th at 12:45 AM

  27. Tom (Richfield Springs):

    36 degrees, calm, overcast. We are losing our snow pack fast.

    Posted January 12th at 5:23 AM

  28. Jill Reale (Utica):

    Good morning! Anyone reporting fog?

    Posted January 12th at 7:06 AM

  29. Denys (East Winfield):

    35 degrees, overcast with a light breeze. We have fog!

    Posted January 12th at 7:37 AM

  30. Denys (East Winfield):

    and light rain…..

    Posted January 12th at 7:38 AM

  31. nugfin (Neil) (South Utica - Genesee St.):

    Filtered sunshine here at 38*...have a feeling I’ll see my lawn by the end of the day, it’s getting really close.

    Posted January 12th at 8:54 AM

  32. Tim (Salisbury):

    Still waiting for the warm up here in Salisbury. Still below freezing,with a little fog.

    Posted January 12th at 9:22 AM

  33. Bill Kardas (WKTV):

    No problems warming up at my house. Up to 45° so far.

    Posted January 12th at 11:07 AM

  34. Adam Musyt:

    Still a few more breaks of sun drifting east from Oswego and Onondaga Counties on the visible satellite.

    Things should work out well for today.

    Posted January 12th at 11:27 AM

  35. Rob (Whitesboro):

    41 degrees here. Had a few peeks of sun. Snowpack is 6” as of this morning.

    Posted January 12th at 11:34 AM

  36. Mel (Westernville):

    Up to 40 degrees here & the meltdown is under way!

    Posted January 12th at 11:52 AM

  37. nugfin (Neil) (South Utica - Genesee St.):

    Up to 47* here with breaks of sun every now and then.

    Buffalo is at 58*

    Posted January 12th at 12:10 PM

  38. Adam Musyt:

    The new GFS run keeps the really cold stuff north of the International border through all of next week.

    If that pans out, the ski resorts will still get to make snow and it’ll be far less of a shock to the system to be outdoors.

    Posted January 12th at 12:21 PM

  39. Rob (Whitesboro):

    Yeah looks alot more seasonable now. It’s good for LES and clippers for the far north. It’s a snoozer for the rest of the country.

    Posted January 12th at 12:34 PM

  40. unwildgirl (Richfield Springs):

    44 degrees and a little cloudy.Went by Canadarago lake this afternoon and couldn’t beleive all the people ice fishing.Ice can’t be that thick..

    Posted January 12th at 4:04 PM

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